Adjustment method for steam extraction and heat supply of large steam turbine

Abstract

The invention relates to an adjustment method for the steam extraction and the heat supply of a large steam turbine; the steam turbine is provided with two working conditions, i.e. straight condensation and steam extraction and heat supply; a steam extraction and heat supply end of the steam turbine is arranged on a reheating section pipeline between the outlet of a boiler re-heater and a medium-pressure main steam valve; two medium-pressure regulating valves are respectively arranged on two parallel reheating section pipelines; when the steam turbine is switched from a straight condensation working condition to the steam extraction and heat supply working condition, the two medium-pressure regulating valves are sequentially and gradually turned off in a steam distribution way through sequential valves, so that the steam extraction and heat supply pressure of the steam turbine is regulated. Consequently, the regulating performance of the medium-pressure regulating valves is improved, so that the pressure of the reheating section of the steam turbine is stabilized in the heat supply and steam extraction pressure scope, the stability and the safety are ensured, energy is saved and emission is reduced, and huge social and economic benefits are created.

Description

technical field [0001] The invention relates to the field of steam extraction and heat supply of steam turbines, in particular to an adjustment method for steam extraction and heat supply of a reheating section of a large steam turbine. Background technique [0002] The heating extraction condensing steam turbine, on the one hand, must ensure the supply of heat required by heat users, and at the same time generate more power, especially during non-heating periods. In the prior art, heating butterfly valves (set on medium and low pressure connecting pipes), rotating baffles, seat cylinder valves, etc. are generally used to control the pressure and flow of heating and extraction steam, and deliver medium and low pressure high-temperature steam to users. [0003] However, large-scale heating extraction condensing steam turbines, especially 300MW and above heating extraction condensing steam turbines, need to satisfy the extraction steam pressure within the range of 3.0MPa ~ 4.2...

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Problems solved by technology

[0003] However, large-scale heating extraction condensing steam turbines, especially 300MW and above heating extraction condensing steam turbines, need to satisfy the extraction steam pressure within the range of 3.0MPa ~ 4.2MPa, and can also adjust the extraction pressure. Steam heating, and the amount of steam extraction is relatively large, the original adjustment method of heating and extraction (such as heating butterfly valve, rotating partition, seat cylinder valve, etc.) is no longer applicable

Moreover, the pressure of the reheating cold section or the reheating hot section of the large steam turbine is generally in the range of 3.0MPa to 4.2MPa. %), it will cause the boiler reheater to overheat, so it can only extract steam from the reheating hot section for heating

If the non-adjustment method is used, the pressure of the reheating hot section will be greatly reduced after extracting steam for heating or when the steam turbine is running at low load, which cannot meet the pressure parameter requirements required by industrial production

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